A horizontal tee allows three cable tray sections to connect, creating a horizontal branch for routing cables efficiently while maintaining structural integrity and NEMA compliance.

Purpose and Function

A horizontal tee is a cable tray fitting used to link three straight channel sections or compatible transitional fittings, forming a horizontal branch in a cable routing system . It is commonly installed where a main cable tray run needs to split into two directions or connect to equipment, enabling organized and efficient cable distribution.

Types of Horizontal Tees

1. Standard Tee (W1 = W2): Connects three sections of equal width, maintaining uniform cable capacity across all branches .
2. Reducing Tee (W1 > W2): Connects a wider main tray to a narrower branch, useful when the branch carries fewer cables .
3. Expanding Tee (W1 < W2): Connects a narrower main tray to a wider branch, accommodating increased cable volume in the branch .

NEMA Classifications

Horizontal tees are designed to match specific NEMA cable tray classes, ensuring compatibility with side rail widths and splice plate configurations:

• Class 1: For NEMA Classes 12B and 12C, with 1 1/8" side rail flanges and 4-hole splice plates.
• Class 2: For NEMA Classes 20A, 20B, and 20C, with 2" side rail flanges and 4-hole splice plates.
• Class 3: For NEMA Classes exceeding 20C, with 2 3/8" side rail flanges and 8-hole splice plates .

Installation Considerations

• Ensure the tee aligns with the main tray and branch to maintain proper cable bend radii and prevent stress on cables .
• Use compatible splice plates and bolts to secure the tee, maintaining structural integrity and grounding continuity .
• Horizontal tees can be used with ventilated or solid-bottom trays depending on cable type and environmental requirements .
• Proper support spacing should follow manufacturer recommendations to minimize deflection and maintain load capacity .

Applications

Horizontal tees are widely used in:

• Data centers and telecommunications rooms for fiber and control cable routing.
• Industrial and commercial installations where multiple cable paths converge.
• Situations requiring neat, organized branching without compromising cable protection or aesthetics . By selecting the correct type and NEMA class, a horizontal tee ensures efficient cable management, structural safety, and compliance with electrical codes.